Automated phone bots keep interrupting your dinner with their pre-recorded marketing messages? Play the U.S. Special Information Tone signal for "vacant circuit" when you pick up the phone. Our brother site Consumerist says a reader who kept getting automated debt collection calls added the tone to the beginning of his voicemail greeting:

The next time the robot called, it thought it was getting a dead line and dutifully erased the number from its system. Voila, automatons be gone. Some places have autodialers that don't (or have been tweaked) to respond to SIT tones, but if you've got a persistent unwanted robot caller, it's worth a shot.

Of course, adding this to your answering machine greeting may confuse genuine human callers as well, but that may be worth scaring off the bots. Grab the tone as a WAV file from the Art of Hacking site. Photo by geishaboy500.